GEMPAK User Stories

User Story 1:

1. Precipitation processes

2. Sounding Manipulation

There are many more lessons like this that I’ve developed over the years, and these are very condensed accounts of them, but it’s a start.

User Story 2:  Senior level synoptic and mesoscale forecasting laboratories ( 2 examples at Iowa State):

We archive the .gem files for upper air, surface, and some models for good cases demonstrating some phenomenon, and thus easy ability to archive the data students will need is essential.  As an example of a lab exercise using real-time data to understand tropical storms and hurricanes, I have students use satellite data with lat/lon overlaid and pick out regions of substantial cloud cover over the tropical Atlantic and Gulf, and tell me if they appear to be organizing in some way.  The students then are told to predict using GFS model data if the system is likely to develop in the next 48 hours, and where it would go.  They are also asked to do the same for the 48-96 h period, and then to explain how much threat they feel a system would be to the U.S.   To do this lab, students use garp to display the satellite images along with enhancements, and they use gdplot to view model predictions of 500 mb flow, 300-850 mb shear, and 700 mb relative humidity.

In another lab using archived data, I have them view images of momentum surfaces (m) and theta-E to diagnose regions where CSI exists.  They also do this using moist potential vorticity overlaid with relative humidity and theta-E contours.  I have used gempak cross-section programs to do this, but in recent years have noticed garp can do this (with a trick to create moist potential vorticity instead of potential vorticity).

User Story 3: HOOT project

The largest University of Oklahoma group who uses GEMPAK is HOOT.  HOOT is a student run forecast product development team, consisting of both undergraduate and graduate students.  HOOT uses C-Shell scripts to process 1000's of images for their website (http://hoot.ou.edu). The primary programs used by the HOOT project are gdplot2, gdplot3, gpmap, snprof, snmap and sfmap.  As HOOT relies on timely processing of data for the generation of a large number of products, initialization of the analysis program is critical. A command line interface for scripting is preferred, as their products are produced on a remote server and they do not wish to run a persistent x-session.

User Story 4:

These are points that were made during an interview of a high end Gempak user who was asked to identify existing capabilities that are critical to be included in AWIPS II.

1. High Degree of Control

2. GUI should be able to access archived data

3. Ability to interpolate to p/v surfaces

 4. Ability to add/modify code.  Subroutines should be transparent so users can modify or use in other programs independent of NAWIPS.

 5. Ability to read/write to/from Fortran

 6. Software should be able to run on standard hardware NOT high end hardware.  Software should be just as fast & efficient as current Gempak